1. Field of the Invention
The present invention relates to quinuclidine carbonate salts which act as muscarinic receptor antagonists. The present invention also relates to methods of preparing such a salt, compositions which contain such a salt, and methods of treating certain conditions by administering such a salt.
2. Discussion of the Background
Quaternary ammonium salts which act as muscarinic (M) receptors antagonists drugs are currently used in therapy to induce bronchodilation for the treatment of respiratory diseases. Examples of well known M receptor antagonists drugs are represented by ipratropium bromide and tiotropium bromide.
Several chemical classes acting as selective M3 receptors antagonists drugs have been developed for the treatment of inflammatory or obstructive airway diseases such as asthma and chronic obstructive pulmonary disease (COPD). Quinuclidine carbamate derivatives and their use as M3 antagonists are described in WO 02051841, WO 03053966, and WO 2008012290.
Said M and M3 receptors antagonists drugs are currently administered through inhalation in order to deliver the drug directly at the site of action and hence limiting the systemic exposure. However, even though the inhalatory route limits the systemic exposure, the known compounds may still exhibit undesired side effects due to systemic absorption.
It is hence highly desirable to provide M3 receptor antagonists drugs able to act locally, while having high potency and long duration of action, and said drugs, once adsorbed, are degraded to inactive compounds which are deprived of any systemic side effects typical of muscarinic antagonists.